DFT calculations of efficient nitric oxide reduction catalysts with metal-free electrocatalysts

Abstract Electrocatalytic reduction of NO to NH ₃ can be achieved by using regenerated electricity to generate NH ₃ with chemical value. The entire process is environmentally friendly and represents a promising strategy for NO emission reduction. The catalytic efficiency of the electrocatalytic NO reduction reaction (NORR) hinges critically on the design and performance of the electrocatalyst. In this study, through first-principles calculations, a series of catalysts were designed, including P single-atom loaded on multi-N-atom doped graphene (P@N _n Gra n = 0–3) for the NORR catalytic process. Through comprehensive evaluation of key descriptors—binding energy, the adsorption strength of NO, and the free energy barrier of the potential-determining step, P@N ₂ Gra and P@N ₃ Gra were ultimately identified as potential NORR catalysts with excellent catalytic activity. Simulation of the entire pathway revealed that the limiting potentials for the NORR process on P@N ₂ Gra and P@N ₃ Gra were –0.176 V and –0.424 V, respectively. Furthermore, analysis of the density of states, charge difference density and crystal orbital Hamilton population elucidated the electronic origin of their high catalytic activity. Ab initio molecular dynamics simulations further confirmed the excellent thermodynamic stability. This study provides a theoretical basis for the regulation strategy of non-metal atoms as active centers of electrocatalysts.